1. Field of the Invention
The present invention relates generally to an air intake method and system of an air conditioner for a vehicle and, more particularly, to an air intake method and system of an air conditioner for a vehicle, which is capable of simultaneously sucking in indoor and outdoor air using a control unit determining whether to draw in indoor air or not according to the temperature of cooling water and the speed of the vehicle, without the need for an additional flap for the intake of indoor air, thus reducing the manufacturing cost.
2. Description of Related Art
As shown in FIG. 1, an air conditioner for vehicles is generally installed in a vehicle. Such an air conditioner appropriately controls the indoor temperature of the vehicle, thus providing a pleasant environment for occupants. A driver heats the interior of the vehicle using the air conditioner in winter. When the interior of the vehicle is heated using the air conditioner for vehicles, the driver can select an indoor air mode or an outdoor air mode. When the indoor air mode is selected, the indoor air of the vehicle is drawn into the air conditioner, and the temperature of the drawn air is increased, prior to being supplied to the interior of the vehicle again. Further, outdoor air may be drawn into the air conditioner and the temperature of the outdoor air may be increased, prior to being supplied to the interior of the vehicle. In order to rapidly increase the indoor temperature in winter, the indoor air mode using indoor air which is higher in temperature than outdoor air is usually conducted. This is advantageous from the point of view of heating, but is problematic in that, as only indoor air circulates, the indoor temperature of the vehicle rapidly increases, so that an excessive amount of moisture is generated on windows due to the abrupt temperature difference between the indoor and outdoor air, thus inconveniencing a driver. Thus, even when the interior of the vehicle is heated in winter, the outdoor air mode is recommended. However, the outdoor air mode is problematic in that energy efficiency is low in terms of heating performance because of the wasted heat of an engine.
Thus, the method of simultaneously drawing in indoor and outdoor air and mixing the drawn air has been proposed.
Conventionally, in order to simultaneously draw in indoor and outdoor air and mix the drawn air, an additional flap F is installed to an indoor and outdoor air control door D which selectively closes an indoor air inlet or an outdoor air inlet. The flap F is opened by the pressure of a blower B during the intake of outdoor air, so that indoor and outdoor air is simultaneously drawn into the air conditioner. However, the conventional air intake method is problematic in that the manufacturing cost is increased due to the installation of the additional flap E In the case where the operation of the blower B is weak, the intake amount of the indoor air is reduced. Even in the case where the indoor and outdoor air are simultaneously drawn in, if a vehicle runs at high speed, the cold outdoor air flows to the blower B, and in addition, may flow into a direction in which the indoor air is drawn. Thus, the initial heating performance of the vehicle has a low efficiency.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.